Few things are more widespread than cell phones. According to Ericsson, the world's largest maker of telecom network gear, in 2009 about 3.6 billion people had mobile phones. That number is growing rapidly. Unfortunately, exchanging information stored in mobile phones when two such devices meet is tedious. Consider sending an email or short message service (SMS) message from one phone to another. First one must ask the owner of the other device for an address; then a message has to be composed and sent. There is too much overhead in this process, especially for canned messages such as one's contact information or a favorite photo.
What is needed is a simple and quick way to exchange information between electronic devices when they physically meet each other. Further, what is needed is a robust method to validate physical meetings of devices so that information is transferred only when intended and only to the intended recipient.